This invention relates to rearview mirrors for vehicles and, more particularly, to a vehicular rearview mirror assembly, and especially an interior central rearview mirror assembly, including mechanical and electrical vibration dampeners/stabilizers which reduce the vibration of an adjustable mirror element as well as its housing.
Rearview mirror assemblies used in motor vehicles, especially interior central rearview mirror assemblies secured to the interior windshield surface, include a manual angular adjustment means allowing movement of the reflective mirror element housing to various positions for viewing traffic and other conditions to the rear of the vehicle. Also, a bearing allows for a slight angular adjustment of the reflective element for nighttime driving. As a consequence of such adjustable mounting, various sources of vibration affect the visibility of images reflected by the mirror element causing both annoyance and a safety hazard. The mirror may also be stabilized because there is play between the mirror and the mirror bracket. Unwanted vibration results from a powered subwoofer creating compression waves that vibrate both the rearview mirror and the windshield upon which the rearview mirror is mounted.
The present invention provides dampening of unwanted vibration keeping the mirror in a stable state where vibrations would normally render the central rearview mirror useless. Also, the invention will allow for angular adjustment of the mirror. In addition, the invention will also add an attractive flicker of light due to the method of dissipation of the vibration energy.
The invention provides a vibration stabilized rearview mirror assembly for vehicles, and especially interior central rearview mirror support assemblies, in which dampeners and stabilizers are mounted against the pivotally adjustable reflective mirror housing assembly. The dampeners are designed so that they define the lower half of the mirror housing and incorporate clamps that stabilize the reflective mirror element. An inertial dampener is also mounted within the assembly to add to the dampening effect.
In one form, the invention is a vibration stabilized rearview mirror support assembly for vehicles including a clamping mechanism and housing structure containing the said clamping mechanism. This clamping mechanism is comprised of two halves of a tubular structure bound by an axle passing through one side of the tubular structures. To keep these structures firmly clamped, a clasp is mounted on one half of the tube and a receiver for the clasp is mounted on the other half. Suspended from the housing structure is a Piezo/clamp support member that is pivoted on a detachable pivot screw that protrudes into the Stabilized Piezo/clamp support member mount located on the underside of the housing structure. From this Piezo/clamp support member Piezo crystal assemblies are mounted to provide a surface to define the lower half of the mirror housing. Also, from the said Piezo/clamp support member, a spring loaded clamping mechanism is mounted to offer support of the mirror reflective element. Mounted within the said housing structure is a circuit card comprised of AC input connection, silicon bridge rectifiers a two-position switch, two LEDs and an output connection.
To further elaborate on said elements of the invention, the Piezo crystal assembly is comprised of a weight supporting a light pressure spring on the Piezo/clamp support member side of the crystal, Piezo crystals and a thin rubber coating containing the entire assembly. These Piezo crystals"" resonate frequencies must be as close as possible to the known resonant frequency of the mirror housing. This is to allow for the greatest vibration dampening efficiency of the crystals. The spring loaded clamping mechanism is comprised of the end of the Piezo/clamp support member, a pivoted spring-loaded spacer containing a pivoted spring loaded pressure block, and a clamp that is made of a soft light conducting plastic. The light conducting clamp houses an LED with leads that run back to an output connection. The clamping assembly is pivoted on the end of the Piezo/clamp support member with a protruding clamp structure that acts as a 1st class lever with the mirror clamp. The said spacer and spring loaded pressure block, when retracted, will provide positive pressure on the protruding clamp structure causing the light conducting plastic clamp to maintain pressure on the reflective element of the mirror. When extended, the pressure is relieved from the protruding clamp structure and in effect, from the reflective element of the mirror. This allows the invention to be attached or removed from the central rearview mirror quickly and easily.
The invention provides at least two methods of dampening which include inertial dampening and Piezo electric dampening. The said inertial dampening is achieved through an inertial dampener mounted within the housing structure. This dampener is comprised of a large Piezo crystal sandwiched between two flexible rubber sheets. The rubber sheets are mounted to the sides of the housing structure and support the mount for the Piezo/clamp support member. On the outside of the said rubber sheets are weights that are allowed to vibrate along with the rubber sheets and the Piezo crystal. In this configuration, the dampener will suppress many of the vibrations caused by the action of the windshield on the mirror structure. Also, a dampening effect occurs because mass is added to the mirror structure. This, in turn, translates into a higher inertia of the mirror assembly yielding less vibration. The purpose of having the inertial dampener support the Piezo/clamp support member is to allow for movement of the Piezo/clamp support member relative to the housing structure. This greatly improves the dampening efficiency of the invention. The invention also provides another mode of Piezo electric dampening where Piezo crystals are utilized again to convert some of the vibration energy from the rear of the mirror housing into electrical energy. The electrical energy from both the Piezo mount crystals and the inertial dampener crystal is then directed through silicon bridge rectifiers to filter the current and then to LEDs housed in both the mirror clamp as well as the housing structure. A two-position switch is provided to choose which LEDs are illuminated.
As will be understood from the various embodiments of the invention, the present vibration stabilized central rearview mirror support assembly for vehicles provides flexibility for the angular adjustment of the mirror housing if needed. The detachable Piezo/clamp support member pivot screw allows for left and right rotation of the Piezo/clamp support member. The Piezo/clamp support member pivot screw""s center of rotation is directly inline with the mirror angle adjustment ball joint""s center of rotation. This is to allow for mirror angle adjustment without expansion or contraction of the Piezo/clamp support member. Alignment of the pivots greatly simplifies the operation and construction of the invention. A friction lock is attached to the Piezo/clamp support member via the friction lock connector and extends to the friction track attached to the inertial dampener located at the rear underside of the housing structure to hold a given angle. The clamping housing allows for adjustment up or down of the mirror bracket at the mirror""s rear ball joint. Also the invention allows for the interchange of clamping structures to accommodate different mirror mount brackets. The Piezo/clamp support member is detachable from the housing structure by removing the Piezo/clamp support member pivot screw and by unplugging the Piezo crystal input to the circuit card and the electrical output to the LEDs found in the mirror clamps. After this is accomplished, the Piezo/clamp support member can be reattached to a housing structure compatible with a given mirror mount bracket. This allows the invention to be used on many styles of central rearview mirror bracket systems.
These and other objects, advantages, purposes and features of the invention will become more apparent from a study of the following description taken in conjunction with the drawings.